BioPlex™ 2200 multiplexed system: Simultaneous detection of anti-dsDNA and anti-chromatin antibodies in patients with systemic lupus erythematosus

Abstract

Background. Antibodies for double-stranded DNA (anti-dsDNA) and chromatin represent specific markers of systemic lupus erythematosus (SLE).

Aims. (1) To evaluate the analytical performance of a multiplexed bead assay (BioPlex™ 2200) for the simultaneous detection of anti-dsDNA and anti-chromatin antibodies, (2) to compare the results for anti-dsDNA with those obtained using Farr assay, and (3) to analyze the clinical relevance of these antibodies when applied to the follow-up of SLE patients with active nephritis.

Patients and methods. Hundred and five clinically characterized SLE patients and 96 healthy blood donors sera were analyzed by BioPlex™ 2200.

Results. Prevalence of these antibodies was significantly higher (p < 0.0001) in SLE patients than in controls (68 and 70% for anti-dsDNA and anti-chromatin, vs. 1% for both anti-dsDNA and anti-chromatin, respectively). If you consider a sample positive if either anti-dsDNA and/or anti-chromatin is positive, then the prevalence of these antibodies reached 78% (82/105) in SLE patients. For anti-dsDNA measurements, the kappa coefficient was 0.59 between BioPlex™ 2200 and Farr assay. Comparison between SLE patients with and without nephritis in a follow-up study showed that patients with active nephritis were associated with an increase of anti-dsDNA and anti-chromatin levels and a reduction of CH50, whereas no variation of antibody levels was observed in SLE patients without nephritis.

Conclusion. Our results demonstrated a benefit of simultaneously measuring anti-dsDNA and anti-chromatin in SLE patients. The BioPlex™ 2200 achieved good analytical performances and proved to be a useful method for monitoring and diagnosing SLE.

• Anti-dsDNA antibodies
• anti-chromatin antibodies
• multiplexed bead assay
• systemic lupus erythematosus

Acknowledgements

The authors would like to thank Dr P. Enel and P. Druard for their expert help in the statistical analysis (Service de santé publique, Hopital de la conception, EA 3279).

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.